Question
ro charge. b) The two atoms are ionic.c) One atom completely A covalent bond is likely to be polar when al the urit formed has no o electron(s) from the other dy One of the atoms is more electronegatv twe than the oher. e) One elkment is ionic and the other is covlernm The primary structure of a nucleic acid relers to: a) The sequence structure of RNA, d] hydrogen bond interactions of 'R groups, e) ncne of Nuclectides, b) the sequence of amino acids, c) the double helo of these are true Which of the folowing molecules is related to the helix structure of ONA? a) Uracil, b) R is a protein (it is a polypeptide) hormone produced by red blood cels. As an Ribose,c) glucoseDooxymbose, e) starch. example of a polypepide, which of the ftolowing is formed by delrydration synthesis c) 'R groups give the polypepbde its Is NOT true? a) t is a sequence of amino acids, b) The polypeptoe shape.d) The polymer chain is made by inking amino ac ds and glycerol e) The amino acids are Irked by peptde bonds. lution because it a) activates the HOE)as polar ructose, a monosaccharide, interacts with H,0 to form an aqueous (water) so properties. c) forms a crystal or solid in water d) s non polar e) dissoclates into ions Can, c) Glycerol + 3 glucose. d) VAr® , d of the folowing foms a positive ion? a) Glycerol 3 fatty acid 24. Steroids (a type af lipid) are NOT water soluble molecules because they are: a) polar, b) have charged parts of their struchure c) non polar d) ionic e) All are true The contents of the cell the cytoplasm) contain mosly HoO with dissolved molecules. However, there are also non-polar molecules (ie, steroids) that function inside the cytoplasm. Based on your understanding of Cherrical evolution, one would expect that these non- polar molecules are a) soluble in water, b) ionicaly charged mclecules, c) attached to polar or lonic groups that alows them to dissolve in the water of the cell's cytoplasm dj are hydrophobic so they interact with the cellular H,0, e) probably these are alltrue ts caled ological macromoleoules are polymers. They: e are large, mokecules formed by inking together repe carbohydrates, and nucleic acids. c) are synthesized by dehydration reactio are correct 27. Which statoment is NOT true about subatomic particles? a) Electrons contain the same mass as neutrons. b) Neutrons have no electrical charge. c) Protons are fourd in the nucleus, d) Electrons are found in orbitals around the nucieus. ej laving & electrons in the outer orbit makes the atom most chemically reactive.un(entrt 28. A molecule that is repelled by or does not interact with the partial charges ftound on the H-0 molecule is termed? aj Hydrostatic b) Polar, c) Non polar, d) Hydrophilic, e) Hypertoric 29. When polar molecules are carefully mixed with water they are observed to exhibit which of the following properties? a) Spontaneous organization into a crystal, b) Separation from the water (H:0) environment because they are hydrophobic, c) Hydrophilic orientation of the polar molecules to the charged portions of the water molacules, d) Miceles form, e) None of these. Of the follwing molecules, which is a complex biolbgical moleculg formed by dehydration synthesis before living organisms existed? Starch, b) Deoxynbonucleic Acid, c) Polypeptide, d) Triglyceride @Al are. 31. Of the folkowing molecules, which has the property of interacting with water by forming ions? a) Glucose, bi. NaCL c) Cellulose, d) Fatty Acids, e) All are 32. Which statement is NOT true about ionic bonds? a) An ionic interaction occurs between positive ions and negative ions. b) Electrons are completely lost or gained in ion formation. c) The two ions share 2 electrons in a covalent bond. d) One atom acts as an electron donor and the other acts as an electron acceptor. e) Li and CI react to form a salt, LiC, by an ionic reaction. Glycogen, a carbohydrate (polysaccharide), that eventually serves as a storage molecule in the evolution of animals (in liver and muscle) because it a) dissolves in water. b) has extra phospho groups.) is a long polymer in which dehydration synthesis has formed very stable bonds between the monomers that do not pass through a lipid bilayer d) ls a protein. e) ls a monomer
Explanation / Answer
For question 21, the correct option is B because to synthesize a protein, ribosomes are made by an enzyme called peptidyl transferase by a somewhat complex mechanism with energy expenditure. Synthesizing hemoglobin by dehydration reactions is impractical and difficult, generally this is done for small peptides (not even the insulin that is a small protein is synthesized by these reactions)
For question 24 Steroids are derived from a mold molecule called sterol, these molecules are non-polar or hydrophobic and tend to repel water, in fact cholesterol (a steroid) is inserted into cell membranes to strengthen the structure of the lipid bilayer
For question 27 The false sentence is that the electrons contain the same mass as the neutrons. Remember that in the atomic model the electrons are small so that they can move between the electronic levels of the atom.
For question 28 Is non polar, remember that i wrote for the question 24
For question 29 is C, remember that polar with polar they get along well together and interact. Instead Polar with non polar they hate an repel.
For question 31 you answer correctly the salt dissociates into sodium and chlorine ions when it comes into contact with water(you may get a little confused about glucose but it interacts with water through the OH groups that you have free and that is why it is solubilized in water).
For question 32 Question 32 is the C if the elements are joined by ionic bond share their electrons, however they do not do so as it is in a covalent bond which has other characters.
